The present invention generally relates to methods for applying plaster-like materials such as stucco, to a building structure, and for restoring/repairing plaster-like materials on a building structure. The present invention also generally relates to fastener systems for use in the above and other methods.
It is well known in the building construction industry, that water intrusion and moisture entrapment in the wall cavities can lead to structural damage and deterioration of internal building components, and often promote the growth of mold, which presents health related issues. Wind-driven rain, water penetrating through cracks in lamina around door or window frame assemblies, and over-spray from irrigation or lawn sprinkler systems, have been the primary sources of water intrusion. Moisture also may condense inside the wall cavity from temperature differentials. All claddings, such as brick, wood, plaster, plaster-like material such as stucco, exterior insulation finish systems (EIFS), or other materials are designed to repel moisture and use gravity to drain the run-off, thereby protecting the underlying substrate surfaces. All wall cavities are susceptible to potential problems if moisture passes through or behind the lamina. If there are no means for drainage or venting within the wall cavity, the moisture cannot escape and mold may grow within the wall cavity. Certain claddings that have greater “wicking” properties enhance moisture migration. Conversely, certain claddings that have water repellant properties enhance moisture retention.
Various exterior system or stucco manufacturers have developed fluid-applied, water resistant, membranes, which are sprayed, brushed, or rolled on the wall assemblies or underlying substrates to form a moisture barrier. After application, the membranes may be allowed to dry or cure. The membranes have unique properties. The microscopic cells of these moisture barrier membranes prevent moisture from transmitting through from the exterior, but are large enough to allow vapor to pass through and exit in the opposite direction. Thus, moisture cannot penetrate the membrane nor enter into the wall cavity. Conversely, the membrane allows vapor to transmit through, escape, or vent out from the wall cavity. The membrane thus advantageously allows the wall to “breath” yet prevents water intrusion.
Certain claddings, particularly one-coat systems, use fasteners that secure a support mesh such as wire netting or a metal lath. These fasteners are driven into the underlying substrates after application of the moisture barrier membrane. The support mesh is subsequently coated with a plaster or similar stucco material as the exterior cladding. The support mesh thus provides something around which the stucco or plaster material will attach. However, any penetrations through the moisture barrier membrane create potential channels for water intrusion.
If the exterior cladding is traditional 3-coat stucco, “EIFS”, one-coat, or similar system, great savings could be derived if the present cladding could be left in place and undisturbed, during repairs. Traditional repair methods concentrated on removal of the cladding, only around the affected area, to expose any hidden damage. This is typically the lower portion of the skirt and directly below window frames, where the migrated water settles at the lowest portion of the building envelope. The exposed wall cavities are air-dried, visible mold is neutralized with bleach, damaged structural framing and sheathing are replaced, and new exterior cladding is reinstalled to blend in with the unaffected facade. These repairs rarely address the cause of water entrapment issues and future problems reoccur soon after repairs are complete.
Building owners demanded permanent solutions to the water intrusion problem because of reoccurring claims. Major damage or second-generation claims, required the entire exterior cladding be removed, so that the repairs could be made and thereafter, new waterproof methods installed. If the entire cladding is removed, tenants and occupants must be relocated due to the dust, noise, exposure to mold spores, and other hazardous issues. Tons of debris added to landfills, including the embedded mold, creates other environmental concerns.
A proprietary restoration system was developed that could completely waterproof the outside building envelope, while keeping much of the existing stucco cladding in place. Like the traditional repair methods, cladding is removed only around the affected area, to expose any hidden damage leaving the original lamina 1 (FIG. 1) intact. This is typically the lower portion of the skirt and directly below window frames, where the migrated water settles at the lowest portion of the building envelope. The exposed wall cavities are air-dried, visible mold is neutralized with bleach, and damaged structural framing 2 and sheathing are replaced. A weep channel 3 is installed at the bottom of the stucco skirt and extends downward over a portion of foundation 4. A new cladding layer 5 is installed where the original cladding was removed. New cladding layer 5 is applied to a thickness corresponding to that of the remaining original cladding 1.
Next, the entire building envelope is waterproofed with a fluid membrane 6 that is either sprayed, brushed, or rolled over the exposed outer surface 7 of both the original cladding 1 and new cladding layer 5. As explained further below, fasteners 8 having washers 9 are then driven through the moisture barrier 6, new/original cladding (1,5) and into studs 2 of the building structure. A support mesh 10 is then hung on the heads of the fasteners 8.
A new stucco cladding facade (not shown) is then installed over the waterproof membrane 6 and support mesh 10. This process offers a vertical waterproof drainage plane, where liquid moisture collects, drains, and escapes through the weep channel 3 at the bottom of the skirt.
The fastener 8 is an intricate part of this system in that it supports the support mesh 10. (i.e., stucco-wire or lath mesh), which is later embedded within a stucco material or similar plaster type cladding facade. A watertight subsurface is critical in preventing future water intrusion. Uniform and thorough membrane 6 application is paramount to the success of the system. Affixing the stucco-wire 10 before the fluid applied membrane 6 to the old lamina 1, creates void areas where non-protected gaps (from netting and fasteners) shield the subsurface from the applied coating. To prevent the voids, the waterproof membrane 6 must be applied to entire subsurface 7 prior to stucco-wire 10 attachment, to ensure total coverage is achieved. Once the membrane 6 is applied, the new stucco wire or lath mesh 10 is fastened over and through the membrane 6 and subsurface 7. Currently, the fasteners used, to secure the stucco wire through the sealed, waterproof membrane, employ the following methods: a) pneumatic nailers with steel pins shot through large metal washers, b) screws with large attached metal washers, or c) screws 8 with large heads and rubber sealing gaskets 9 (neoprene washers). Both a) and b) designs, create leaks surrounding the penetrations. Even using neoprene washers 9 and screws 8, the c) style, fastening design, was subject to system failure if the rubber washers did not seal properly (due to under/over driven screws or from expansion/contraction of building components).